This Method is Compatible with Every Apple iPhone jailbreak required .

This will fix any problem you have with your internet GSM detector, many unlocked iphones there are possible using any extra sim card to unlock carrier. you can use this tutorial to fix any 3G – 4G or LTE Problem.

how you need to fix this
1- Jailbreak your iphone first
2: Install iFile
3: Open iFile
4: Navigate to /System/Library/Carrier Bundles/iPhone
5: Find you Sim Card Company Name Folder and Delete that Folder
6: Restart your iPhone

PLEASE NOTE – If you can’t find your carrier folder,
please go to iPhone
Settings — General — About — Carrier – You can see your carrier name here on the right side.